Coordinated Regulation of Virulence Genes in C. neoformans

项目摘要。在被感染的宿主的恶劣环境中生存，致病 微生物必须能够感知并适应不断变化的环境条件。这 适应需要对生长和生存的多种因素进行协调调节。像许多人一样 感染剂，人类真菌病原体新生隐球菌使用保守的 信号分子环磷酸腺苷(CAMP)调节其对外界压力的反应。中环 CAMP信号转导通路的组成在微生物中高度保守。 然而，这一提议的主要假设是，上游激活信号和 CAMP的下游效应物在功能上专用于微生物病原体。这 专门化允许病原微生物使用cAMP信号来控制它们的毒力 潜力。 CAMP产量的增加激活了一系列蛋白质相互作用，使C. 以适应宿主环境。具体地说，新生梭菌的cAMP途径 调节胶囊和黑色素的诱导，这是致病所需的两种细胞因子。这 调控发生在转录水平上。因此，这一提议的实验将 识别介导cAMP影响的反式和顺式作用的调控元件 胶囊相关基因的转录。此外，定义受控的监管网络 通过cAMP依赖的转录因子将使我们能够探索环境中的广泛问题 感知、细胞压力和微生物毒力。具体目标1提出生物信息学和 用转录图谱方法鉴定控制新生葡萄球菌的转录因子 胶囊基因表达。特定目标2概述了对选定转录的详细测试 以确定它们在包膜诱导中的作用。具体目标3中的实验将定义 前两个目的中确定的转录因子的直接和间接靶基因。

Project Summary. To survive within the hostile environment of the infected host, pathogenic microorganisms must be able to sense and adapt to changing environmental conditions. This adaptation requires a coordinated regulation of multiple factors for growth and survival. Like many infectious agents, the human fungal pathogen Cryptococcus neoformans uses the conserved signaling molecule cyclic AMP (cAMP) to regulate its response to external stresses. The central components of cAMP signal transduction pathways are highly conserved among microorganisms. However, the main hypothesis of this proposal is that the upstream activating signals and the downstream effectors of cAMP are functionally specialized in microbial pathogens. This specialization allows pathogenic organisms to use cAMP signaling to control their virulence potential. Increased cAMP production activates a series of protein interactions that allows C. neoformans to adapt to the host environment. Specifically, the C. neoformans cAMP pathway regulates the induction of capsule and melanin, two cellular factors required for pathogenesis. This regulation occurs at the level of transcription. Therefore, the experiments of this proposal will identify trans- and cis-acting regulatory elements that mediate the effect of cAMP on the transcription of capsule-associated genes. Moreover, defining the regulatory networks controlled by cAMP-dependent transcription factors will allow us to explore broad issues in environmental sensing, cellular stress, and microbial virulence. Specific Aim 1 proposes bioinformatic and transcriptional profiling approaches to identify transcription factors that control C. neoformans capsule gene expression. Specific Aim 2 outlines detailed testing of selected transcriptional regulators to define their role in capsule induction. Experiments in Specific Aim 3 will define the direct and indirect target genes of the transcription factors identified in the first two Aims.